2 Research recommendations

The Guideline Development Group has made the following recommendations for research, based on its review of evidence, to improve NICE guidance and patient care in the future. The Guideline Development Group's full set of research recommendations is detailed in the full guideline (see section 5).

2.1 Nasal decontamination

Is it cost effective to use mupirocin for nasal decontamination? In which patients is it most effective?

Why this is important

This is important as it is not clear how many surgical site infections would be prevented by treating all patients with nasal mupirocin, or whether only patients who are nasally colonised with methicillin-resistant Staphylococcus aureus should be treated. The use of mupirocin and its application is cost- and time-sensitive, apart from the concern that excessive use of mupirocin may lead to resistance. There should be further research involving large numbers of study participants undergoing different operations.

2.2 Maintaining patient homeostasis

2.2.1 Oxygenation

What is the value of supplemented oxygenation in the recovery room in the prevention of surgical site infection? What are the likely mechanisms of action?

Why this is important

There have been several randomised control trials (RCTs) that show a contradictory effect of supplemental oxygenation in the recovery room period, some showing benefit, some not. Two separate trials indicate that surgical site infection rates can be halved simply by increasing the amount of inspired oxygen. However, a fraction of inspired oxygen (FiO2) of 0.8 cannot be achieved using a face mask, and all patients already receive an increased FiO2 to give a haemoglobin saturation of at least 95% by their anaesthetist during the operation and in the immediate postoperative period. The mechanism for improved blood oxygen carriage due to increased FiO2 is physiologically not clear. However, this simple, cheap intervention deserves further investigation.

2.2.2 Perioperative blood glucose control

What are the possible benefits of improved postoperative blood glucose control on the incidence of surgical site infection?

Why this is important

There have been several large cohort studies in cardiac surgery which indicate that tight postoperative blood glucose control can reduce the risk of surgical site infections, and the serious complication of sternal incision infection in particular. A blood glucose level above the normal range is typical after major trauma and has been considered part of the 'normal' metabolic response. Further studies should be adequately powered RCTs covering a wide range of surgical procedures to show unequivocally that tight blood glucose control is acceptable (even if it lowers the risk of surgical site infections in general) as the lowering of glucose in the immediate postoperative period may have unwanted complications and will require added careful surveillance. Again, the physiological mechanisms that reduce the risk of surgical site infection are not entirely clear.

2.3 Closure methods

What types of closure methods will reduce the risk of surgical site infection?

Why this is important

Although there are many studies in the field of wound closure, there are still several areas in which questions remain unanswered. Natural suture materials such as catgut and silk have been replaced by tailor-made absorbable and non-absorbable polymers. However, more research is needed to convince surgeons to stop using mass closure of the abdominal wall or subcuticular sutures for skin closure, as these methods have become standard practice. The use of monofilaments or braids also depends on personal preference and further trials are unlikely to show differences in surgical site infection. There are data to show some techniques can allow more rapid closure, such as the use of staples or adhesive acrylate glues. Again, these have other disadvantages that could only be proven in what would be large, single-intervention RCTs. Further research is required on use of different suture materials and skin adhesives and their effect on the rate of surgical site infection. Research should be multi-centred, adequately powered, single-intervention RCTs. Studies should also include the cost effectiveness of different closure methods.

2.4 Wound dressings

What is the benefit and cost effectiveness of different types of post-surgical interactive dressings for reducing the risk of surgical site infection?

Why this is important

There are a huge number of dressings available for chronic wound care that could also be used for incisional sites. The use of island dressings compared with simple adhesive polyurethane transparent dressings is an example of a study that could be undertaken with outcomes of reductions in surgical site infections and also reductions in skin complications and improvements in final cosmetic outcomes. However, current studies are not adequate to show convincing differences. Research is also required on the effects of antiseptic-bearing dressings, placed at the end of an operation or at dressing changes. These antiseptics could include povidone-iodine, biguanides (such as chlorhexidine) or silver.

2.5 Dressings for wound healing by secondary intention

What are the most appropriate methods of chronic wound care (including alginates, foams and hydrocolloids and dressings containing antiseptics such as antimicrobial honey, cadexomer iodine or silver) in terms of management of surgical site infection as well as patient outcomes?

Why this is important

There are many small cohort studies which have examined the use of the wide range of dressings in surgical site infection management after an infected wound has been opened or after there has been separation of the wound edges after a surgical site infection. Differences are hard to see because the trials often include other wounds that are healing by secondary intention, such as chronic venous or diabetic ulcers and pressure sores. Specific studies using antiseptics (povidone-iodine, biguanides such as chlorhexidine, or silver) and other agents such as antimicrobial honey need to address this in powered randomised trials, specifically in the management of surgical site infection of an open wound. Similar questions need to be asked for the use of topical negative pressure, which has become widely used with or without antiseptic irrigation.

  • National Institute for Health and Care Excellence (NICE)